Modification of plant lipids and seed oils utilizing yeast SLC genes

ABSTRACT

This invention relates to the modification of plant lipids and seed oils by genetic engineering techniques to produce oilseeds of enhanced commercial value. In one form, the invention relates to a transgenic oilseed plant, or a seed of such plant, having a genome incorporating an expressible yeast SLC1-1 or SLC1 gene. The invention also provides a method of producing a transgenic oilseed plant, which comprises introducing into the genome of the plant an expressible yeast SLC1-1 or SLC1 gene. The invention also relates to various plasmids and vectors used in the method of the invention.

TECHNICAL FIELD

This invention relates to the modification of plant lipids and seed oils by genetic engineering techniques. More particularly, the invention relates to a method of genetically modifying oilseed plants to produce oilseeds or whole plants of enhanced commercial value. The invention also relates to the modified plants and seeds, and to genetic materials and vectors used for the production of such plants, and for further modifications of plants.

BACKGROUND ART

There is considerable interest nowadays in modifying the seed oil fatty acid composition and content of oilseeds by molecular genetic means to provide a dependable source of Super High Erucic Acid Rapeseed (SHEAR) oil for use as an industrial feedstock. A similar interest exists for producing other strategic non-edible oils (e.g. seed oils high in hydroxy-, epoxy-, short and medium chain fatty acids, etc.) in traditional oilseed crops (e.g. rapeseed, flax, sunflower, soybean).

For edible oils, there is considerable interest in changing the fatty acid composition (e.g. higher oleic/lower polyunsaturates, lower saturates, higher saturates) as well as increasing the oil content in oilseed crops such as Canola and edible oil flax (Linola), soybean and sunflower.

Currently, there are no documented demonstrations of increases in oil content (yield) by transgenic means, although yield increases by traditional breeding and selection continue to bring about incremental improvements.

In contrast, increases in the proportions of some strategic fatty acids have been achieved by the introduction of various plant fatty acid biosynthesis and acyltransferase genes in oilseeds. Some examples of such processes are the following:

1. Expression of a medium chain fatty acyl-ACP thioesterase from California Bay, in Brassicaceae to increase the lauric acid (12:0) content (Calgene; Voelker et al., 1992; 1996--see References 35 and 36 in the accompanying "References Pertinent to the Present Invention").

2. Expression of a Jojoba β-ketoacyl-CoA synthase in low erucic acid Brassica napus (Canola) cultivars to increase the level of erucic acid; the effect following expression in high erucic acid cultivars was negligible (Calgene; Lassner et al., 1996--see Reference 20).

3. Expression of an anti-sense construct to the stearoyl-ACP Δ9 desaturase in Brassicaceae to increase the stearic acid content (Calgene; Knutzon et al., 1992--see Reference 16).

4. Increased proportions of oleic acid in B. napus by co-suppression using a sense construct encoding plant microsomal FAD2 (Δ12) desaturase (duPont/InterMountain Canola; Hitz et al., 1995--see Reference 12).

5. Increased proportions of 12:0 or 22:1 in the sn-2 position of triacylglycerols (TAGs) in rapeseed by expression of coconut or meadowfoam lyso-phosphatidic acid acyltransferases (LPATs; E.C. 2.3.1.51), respectively (Calgene; Knutzon et al., 1995 a & b;--see References 17 and 18; Lassner et al., 1995--see Reference 21).

Although the use of plant transgenes resulted in altered proportions of sn-2 lauric and erucic acids, in laurate canola and high erucic acid rapeseed, respectively, the overall proportions of lauric and erucic acids in the seed oil were not increased, and there was no evidence of increased total fatty acid content, or increased oil yield in these transgenics.

There is accordingly a need for new ways of increasing oil yield and improving oil composition in oilseed plants by employing genetic engineering techniques.

DISCLOSURE OF INVENTION

An object of the present invention is to genetically modify oilseed plants to improve the commercial value of such plants, the seeds of such plants, and the oils produced from such plants.

Another object of the invention is to provide a method of modifying the yield and composition of oils derived from oilseed plants.

The present invention is based on the discovery that sn-2 acylglyceride fatty acyltransferase genes (SLC1-1 and its allele, SLC1) from yeast (Saccharomyces cereviseae), can be used to change the oil content and oil composition of plant seed and leaf lipids.

Thus, according to one aspect of the present invention, there is provided a transgenic oilseed plant having a genome incorporating an expressible yeast SLC1-1 or SLC1 gene.

According to another aspect of the invention, there is provided a seed of a transgenic oilseed plant having a genome incorporating an expressible yeast SLC1-1 or SLC1 gene.

According to yet another aspect of the invention, there is provided a method of producing a transgenic oilseed plant, which comprises introducing into the genome of said plant an expressible yeast SLC1-1 or SLC1 gene.

The invention also relates to various plasmids and vectors used in the method of the invention, and to the co-introduction of other genes into plants modified to include the SLC1-1 and SLC1 genes.

The advantages of the present invention include the fact that the yeast SLC1-1 and SLC1 genes can be used to increase the oil content and to change total fatty acid composition, as well as to alter the acyl composition of TAGs, including the sn-2 position, and to change the relative proportions of TAG species, in various oilseed plants, e.g. Arabidopsis thaliana, in high erucic acid and canola cultivates of Brassica napus, and in Brassica carinata.

Moreover, the yeast sn-2 acyltransferase (SLC1-1 and SLC1 genes) can be utilized in high erucic acid Brassicaceae to increase the oil content and to produce seed oils with increased content of very long-chain fatty acids (VLCFAs) and TAGs with an altered stereospecific composition with respect to very long chain fatty acids. Thus, in contrast to previous results utilizing plant transgenes (as mentioned above), the current invention utilizing a yeast transgene is capable of achieving combined increases in seed oil content, seed erucic acid content and overall proportions of erucic acid in the seed oil.

The yeast sn-2 acyltransferase (SLC1-1 and SLC1 genes) can also be utilized in edible oil cultivars (Canola-quality cultivars) of the Brassicaceae, to increase the oil content and to produce seed oils with altered proportions of oleic acid, polyunsaturated fatty acids and very long chain saturated fatty acids.

The related yeast SLC1-1 and SLC1 alleles can be utilized in the same ways. Both alleles encode an sn-2 acyltransferase; SLC1 differs from SLC1-1 only in the amino acid at position 44 (Glutamine, Q) compared to SLC1-1, where the amino acid at position 44 is Leucine (L).

The SLC1-1 and SLC1 transgenic plants can be used as host germplasm for further down-regulation of endogenous plant acyltransferases.

To achieve directed assembly of TAG biosynthesis to produce stereospecifically-designed TAGs, the co-ordinated expression of a number of biochemical reactions, including that mediated by LPAT, is required. One of the distinct possibilities with respect to optimizing transgenic expression of foreign LPATs to synthesize TAGs with new acyl composition (e.g. increased very long chain fatty acids at the sn-2 position), is the possible need to simultaneously down-regulate the endogenous LPAT already present in the transgenic host (e.g. an LPAT which normally prefers to insert polyunsaturated C₁₈ fatty acyl groups into the sn-2 position). The overall homologies between the yeast sn-2 acyltransferases and published plant sn-2 acyltransferases (LPATs) are low, and are restricted mostly to the C-termini of the proteins. In contrast, the plant acyltransferases have much greater overall homology to each other, and regions of homology extend throughout the sequence. Therefore, the use of the yeast SLC genes to achieve the effects described herein, allow a unique opportunity to further improve these traits in a way not possible when the initial transformation was performed with a plant acyltransferase. In effect, the limited homology between plant and the yeast sn-2 acyltransferases are low enough to allow strategies to down-regulate the host plant LPAT by conventional means (e.g. anti-sense RNA technology or a co-suppression phenomenon; Mol et al., 1990; Van Blokland et al., 1993; De Lange et al., 1995) without a concomitant negative impact on the expression of the yeast transgene or on plant seed development. Thus, the yeast transgene strategy has a distinct advantage over that in which another plant transgene is introduced into a host plant where there is a highly homologous, endogenous LPAT.

The yeast sn-2 acyltransferase (SLC1-1 and SLC1 genes) can be used to increase the oil content and alter the acyl composition of TAGs in all other oilseeds including borage (Borago spp.), castor (Ricinus communis), cocoa bean (Theobroma cacao), corn (Zea mays), cotton (Gossypium spp), Crambe spp., Cuphea spp., flax (Linum spp.), Lesquerella and Limnanthes spp., nasturtium (Tropaeolum spp.), Oenothera spp., olive (Olea spp.), palm (Elaeis spp.), peanut (Arachis spp.), safflower (Carthamus spp.), soybean (Glycine and Soja spp.), sunflower (Helianthus spp.), tobacco (Nicotiana spp.) and Vernonia spp.

The yeast sn-2 acyltransferase (SLC1-1 and SLC1 genes) oilseed transformants can be utilized, by a second transformation, with all other value-added fatty acid biosynthesis genes (e.g. the hydroxylase gene from castor or Lesquerella spp.), or by crossing with related oilseed transformants already containing such value-added genes, to produce seed oils with increased amounts of value-added fatty acids (e.g. increased hydroxy fatty acid content and altered TAG composition with respect to those containing hydroxy fatty acids).

The SLC1-1 gene and related SLC1 allele, can be utilized to modify fatty acid and lipid profiles in vegetative tissues to improve tolerance to biotic and abiotic plant stresses (e.g. increased membrane fluidity in root and leaf tissues to improve frost tolerance).

The use of the yeast SLC1-1 gene and the SLC1 allele in plants, to bring about changes in overall lipid content and composition, has not been previously disclosed or demonstrated (reduced to practice) as a means for manipulating the relative proportions or amounts of fatty acids (e.g. very long chain fatty acids), and also for increasing the oil content of crops producing edible or industrial oils.

Previously, there have been no demonstrations of increases in oil yields brought about by transgenic means. More specifically, there was no previous evidence that yeast acyltransferases, the enzymes responsible for synthesizing triacylglycerols, have been expressed in plants to alter oil composition or content.

In contrast, however, a decrease in diacylglycerol acyltransferase activity in a mutant of Arabidopsis thaliana resulted in a decrease in oil yield and a change in acyl composition (Katavic et al., (1995) Plant Physiology, 108:399-409--see Reference 15).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the nucleotide [SEQ ID NO:1] and deduced amino acid sequence [SEQ ID NO:2] of the coding region of the yeast SLC1-1 gene used in the present invention, the stop codon being identified by "@", and a highly conserved consensus sequence among bacterial and yeast sn-2 acyltransferases being underlined;

FIG. 2 shows the nucleotide [SEQ ID NO:3] and deduced amino acid sequence [SEQ ID NO:4] of the coding region of the yeast SLC1 gene used in the present invention, the stop codon being identified by "@", and a highly conserved consensus sequence among bacterial and yeast sn-2 acyltransferases being underlined;

FIG. 3 shows a strategy for constructing an SLC1-1 plant transformation vector explained in the Experimental Details provided later, the salient features not being drawn to scale; and

FIGS. 4 to 7, as well as Tables 1-20 below, show the results of tests explained in the Experimental Details provided later.

BEST MODES FOR CARRYING OUT THE INVENTION

The sequences of the SLC1-1 gene [SEQ ID NO:1] and the SLC1 allele [SEQ ID NO:3], and their derived peptide structures [SEQ ID NOS: 2 and 4], are as shown in FIGS. 1 and 2, respectively.

The yeast SLC1 gene (and related SLC1-1 suppressor allele gene) have been characterized in two publications, as follows (the disclosures of which are incorporated herein by reference);

1. Lester, R. L., Wells, G. B., Oxford, G. and Dickson, R. C. (1993) Mutant strains of Saccharomyces cerevisiae lacking sphingolipids synthesize novel inositol glycerolipids that mimic sphingolipid structures. J. Biol. Chem. 268: 845-856--Reference 22; and

2. Nagiec, M. M., Wells, G. B., Lester, R. L., and Dickson, R. C. (1993) A suppressor gene that enables Saccharomyces cerevisiae to grow without making sphingolipids encodes a protein that resembles an Escherichia coli fatty acyltransferase. J. Biol. Chem. 268: 22156-22163--Reference 25.

The DNA and amino acid sequences for the coding region of the SLC1-1 gene are stored in GenBank/EMBL under accession No. L13282 (the stored sequence including a 5' untranslated region not disclosed in the present application).

The SLC1 gene was originally cloned from a yeast mutant lacking the ability to make sphingolipids. The mutant allele of SLC1 was shown to encode a protein which suppresses the genetic defect in sphingolipid long chain base biosynthesis. The gene sequence of SLC1 is homologous to the E. coli PLSC gene, which has been claimed to encode lyso-phosphatidic acid acyltransferase (LPAT; and acyltransferase acylating the sn-2 position of lyso-phosphatidic acid (LPA) to give phosphatidic acid (PA)). The SLC1 gene was able to complement the growth defect in JC201 (an E. coli strain mutated in PLSC). Based on the observation that SLC strains grown in the absence of long chain base make novel phosphatidylinositol derivatives (Lester et al., (1993) J. Biol. Chem. 268: 845-856.), one possible conclusion by the authors was that the SLC1 encodes a protein capable of acylating the sn-2 position of inositol-containing glycerolipids (i.e. perhaps an lyso-phosphatidyl-inositol acyltransferase, LPIT). Based on these findings, it was reported that SLC1 encodes a yeast sn-2 acyltransferase. However, the authors of the paper (Dickson, Lester et al.), were unable to detect LPAT activity in the complemented E. coli JC201 mutant.

In the Nagiec et al. paper, the authors also reported the sequence of the gene for a suppressor allele designated SLC1-1 in which nucleotide 131 has a T instead of an A, resulting in an amino acid change at position 44, from a glutamine to a leucine. The working hypothesis is that the SLC1-1 suppressor allele encodes a variant acyltransferase with an altered substrate specificity, which enables it to use a very long-chain fatty acid (26:0) to acylate the sn-2 position of inositol-containing glycerolipids. The authors have not, to date, provided conclusive evidence of activity encoded by SLC1-1 or SLC1.

Based on the interest of the inventors of the present invention in modifying the very long-chain fatty acid (VLCFA) content of Brassicaceae, the inventors obtained plasmid p411 ΔB/C containing the SLC1-1 suppressor allele gene from Dr. Dickson at the University of Kentucky, Lexington, Ky., USA. The inventors also believed that expressing the foreign gene in a plant might lead to more information in the nature of what SLC1-1 and SLC1 encode. Work carried out by the inventors identified, for the first time, using the model oilseed Arabidopsis thaliana, transformants with increased seed oil content, and increased proportions of TAGs containing very long-chain fatty acids (VLCFAs=>C₁₈). In addition, there are increased proportions of VLCFAs at the sn-2 position of TAGs, and a concomitant decrease in the proportion of polyunsaturated fatty acids esterified at this position. SLC1-1 transformants of B. napus cv. Hero and B. carinata (both high erucic acid cultivars) show increased oil content and increased erucic acid content/mg dry weight (DW) of seed. SLC1-1 transformants of B. napus cv. Westar (Canola-quality cultivar) show increased proportions of oleic acid (18:1) and decreased proportions of polyunsaturated fatty acids (18:2 and 18:3).

The SLC1-1 and SLC1 genes can be introduced into the genomes of oilseed plants and expressed using conventional genetic engineering techniques. For example, transformation could involve the use of Agrobacterium Ti plasmid-mediated transformation (e.g. in planta, vacuum infiltration, cotyledonary or hypocotyl petiole wound infection, or particle bombardment, etc). Constructs may be driven by constitutive or tissue-specific promoters, as will be apparent to persons skilled in the art.

Broad applicability of the invention to oilseed plants of various kinds is to be expected because oil synthesis follows the same or closely related biochemical pathways in all such plants (see References 29, 30, 37, 38, 39 and 40).

The present invention will be described in more detail with reference to the following experimental details, which provide specific illustration. It should be kept in mind, however, that the present invention is not limited to the details presented below.

EXPERIMENTAL DETAILS

CONSTRUCTION OF VECTORS FOR SLC1-1 TRANSFORMATION

Following the cloning strategy illustrated in FIG. 3 of the accompanying drawings, two primers with 5' BamHI restriction site extensions, OM087 (AGAGAGAGGGATCCATGAGTGTGATAGGTAGG) [SEQ ID NO: 5] and OM088 (GAGGAAGAAGGATCCGGGTCTATATACTACTCT) [SEQ ID NO:6], designed according to the 5' and 3' end sequences of the SLC1 gene [SEQ ID NO:3], respectively, were used in a Polymerase Chain Reaction (PCR) with plasmid p411ΔB/C (obtained from Dr. Dickson at the University of Kentucky, Lexington, Ky., USA), harboring the suppressor allele of the SLC gene (SLC1-1) as template, to generate the SLC1-1 PCR fragment with a BamHI site at both ends. The (SLC1-1) PCR fragment, therefore, represents the suppressor allele of the SLC1 gene with nucleotide T substituting for nucleotide A at position 131, resulting in an amino acid residue change from glutamine to leucine at residue 44. The fragment was digested with BamHI and ligated into the BamHI cloning site located between the tandem 35S promoter and NOS terminator in vector PBI524 (obtained from Dr. Raju S. S. Datla, NRC Plant Biotechnology Institute, 110 Gymnasium Place, Saskatoon, Saskatchewan, Canada, S7N OW9; published by Datla et al., 1993--see Reference 9) to give vector SLC1-1-pBI-524. The orientation of SLC1-1 in the vector SLC1-1-pBI-524 was verified by restriction digestion with BglII which cuts SLC1-1 at nt 377 from the 5' end and immediately downstream of the 35S promoter in vector pBI524. The translation initiation codon of SLC1-1 is maintained, and hence the construct is a transcriptional fusion. The HindIII and EcoRI fragment containing a tandem 35S promoter, AMV enhancer, SLC1-1 encoding sequence and NOS terminator was freed from SLC1-1-pBI-524, and cloned into the EcoRI-HindIII site of vector RD400 (also obtained from Dr. R. Datla; published by Datla et al., 1992--see Reference 8). The final vector pSLC1-1/pRD400 (deposited on May 9, 1996 under the terms of the Budpest Treaty at the American Type Culture Collection, 10801 University Blvd., Manassas, Va. 20110-2209, USA; under deposit no ATCC 97545) was introduced into Agrobacterium tumefaciens strain GV3101 (bearing helper plasmid pMP90; Koncz and Schell, 1986) by electroporation.

MOLECULAR BIOLOGICAL TECHNIQUES

Unless otherwise stated, all molecular biological techniques were carried out by methods generally prescribed by Ausubel et al., (1995).

PLANT GROWTH CONDITIONS

All A. thaliana control and transgenic plants were grown at the same time, in controlled growth chambers, under continuous fluorescent illumination (150-200 μE·m⁻² ·sec⁻¹) at 22° C., as described by Katavic et al., (1995). All other control and transgenic plants of the Brassicaceae (B. napus, B. carinata) were grown at the same time, in the P.B.I. Transgenic Plant Center greenhouse under natural light supplemented with high pressure sodium lamps (HPS lamps) with a 16 hour photoperiod (16 h light/8 h dark), at 22° C., and a relative humidity of 25-30%.

PLANT TRANSFORMATION

The SLC1-1/RD400 construct was tested in A. thaliana by in planta transformation techniques, and in both high and low erucic acid B. napus cultivars, and B. carinata (by co-cultivation transformation of cotyledonary petioles and hypocotyl explants with A. tumefaciens bearing the SLC1-1 construct).

Testing the SLC1-1 construct in A. thaliana

Wild type (WT) A. thaliana plants of ecotype Columbia were grown in soil. In planta transformation was performed by wound inoculation (Katavic et al. 1994) or vacuum infiltration (Bechtold et al. 1993) with overnight bacterial suspension of A. tumefaciens strain GV3101 bearing helper nopaline plasmid pMP90 (disarmed Ti plasmid with intact vir region acting in trans, gentamycin and kanamycin selection markers; Koncz and Schell (1986)) and binary vector pSLC1-1/pRD400.

After inoculation or infiltration, plants were grown to set seeds (T₁). Dry seeds (T₁) were harvested in bulk and screened on selective medium with 50 mg/L kanamycin. After two to three weeks on selective medium, seedlings were transferred to soil. Lead DNA was isolated from kanamycin-resistant T₁ plants and analysed by PCR amplification of the SLC1-1 fragment. Developing leaves from T₁ plants as well as T₂ mature seeds from SLC1-1 transgenic lines were used for lipid and biochemical analyses. Developing leaves and mature seeds from untransformed wild type (WT) Columbia plants and pBI121 transgenic plants (binary vector pBI121, containing only kanamycin selection marker and GUS reporter gene; Jefferson et al., 1987) were used as controls in analyses of seed lipids. Based on these analyses, T₂ seeds of lines exhibiting changed acyl composition and/or lipid content were grown on selective medium (to eliminate homozygous WT segregants) and then transferred to soil to yield T₃ seed populations.

Testing the SLC1-1 construct in Brassica napus and Brassica carinate:

Transformation experiments were also performed on B. napus cv. Westar (canola variety, low erucic acid), B. napus cvs. Hero, Reston and Argentine (all high erucic acid varieties) and B. carinata (breeding line C90-1163, a high erucic acid line) by co-cultivation of cotyledonary petioles and hypocotyl explants with A. tumefaciens bearing the SLC1-1/RD400 construct. Transformation methods according to Moloney et al.(1989) and DeBlock et al.(1989) were modified to optimize transformation conditions.

Modifications of the cotyledonary-petiole transformation method (Moloney et al., 1989) included the introduction of a 7-day explant-recovery period following co-cultivation, on MS medium with the hormone benzyladenine (BA) and the antibiotic timentin, for elimination of Agrobacterium.

Modifications of the hypocotyl-explant transformation method (DeBlock et al.; 1989) included: (1) preculture of explants on agar-solidified MS medium with the hormones 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin (K); (2) co-cultivation of hypocotyl explants with Agrobacterium in petri dishes with the same medium as for preculture, on sterile filter paper; (3) following co-cultivation, a 7-day explant-recovery period on medium with hormones (2,4-D and K), and with timentin for Agrobacterium elimination, (4) regeneration of transgenic shoots on MS medium with the hormones benzyladenine (BA) and zeatin (Z), the ethylene inhibitor silver nitrate (AgNO₃), and antibiotics timentin (for Agrobacterium elimination) and kanamycin (for transformed-cell/shoot selection).

Green shoots were rooted and transferred to soil. Genomic DNA was isolated from developing leaves and PCR analyses and Southern analyses (Southern, 1975) were performed. Seeds (T₁) from transgenic plants were harvested and from each transgenic line, ten T₁ plants were grown in soil. Mature seeds (T₂) from these plants were harvested and subjected to lipid and biochemical analyses.

LIPID ANALYSES AND ACYLTRANSFERASE (LPAT) ASSAYS

Analyses of Leaf and Seed Lipids from SLC1-1 and WT/pBI121 Transgenics and Untransformed WT plants

Lipids were isolated from mature seed and developing leaves as described previously (Taylor et al., 1992; Katavic et al, 1995) and analyzed by GC for total fatty acid content and fatty acid composition. Triacylglycerol species were analyzed by high-temperature GC as described by Katavic et al., 1995. Stereospecific analyses of TAGs were performed on intact seed lipids (chiefly TAGs) as described by Taylor et al., 1994, 1995 a & b).

LPAT assays

For leaf assays, leaves at mid-expansion were chosen from control and SLC1-1 transgenic plants, and leaf tissue sampled from several leaves with a cork-borer. For developing seed assays, in A. thaliana 25-30 silques were harvested at mid-seed development (15-18 d.p.a.) to give developing T₃ seed samples from both controls (untransformed WT and pBI121-transformed) and selected SLC1-1 transgenics. B. napus and B. carinata T₂ embryos at the mid cotyledonary stage of development were harvested from 3 siliques of control and selected SLC1-1 transgenic plants. All plant material was frozen immediately in liquid nitrogen and stored at -70° C. until homogenized. Homogenates of both plant leaf and developing seed tissues were prepared and LPAT assays conducted as described by Taylor et al., (1995b).

All protocols with respect to yeast strains were carried out as described by Ausubel et al., (1995, Unit 13.1 Basic Techniques of Yeast Genetics). Wild-type S. cerevisiae and S. pombe strains were cultured in YPD medium at 28° C. at 270 r.p.m. overnight. At mid-log phase, cells were sampled, pelleted by centrifugation at 5,000 r.p.m. for 5 min, and resuspended in 100 mM Hepes-NaOH, pH 7.4. Cell lysates were prepared using acid-washed glass beads as described by Ausubel et al., 1995 (Unit 13.1, Section 13.13.4).

LPAT assays were conducted at pH 7.4, with shaking at 100 r.p.m., in a water bath at 30° C. for 10-30 min. Assay mixtures (0.5 mL final volume) contained protein (10-200 μg, depending on the tissue/extract), 90 mM Hepes-NaOH, 0.5 mM ATP, 0.5 mM CoASH, 2 mM spermidine, 45 μM 18:1-LPA, and either 18 μM [1-¹⁴ C]-18:1-CoA, [1-¹⁴ C]-20:1-CoA, or [1-¹⁴ C]-22:1-CoA (each at a specific activity of 10 nCi/nmol) as the acyl donor. All other conditions for the measurement of LPAT activity are as detailed in Taylor et al (1995b).

¹ H-NMR of Mature Seeds

¹ H-NMR analyses for relative oil yield (Alexander et al., 1967; Rutar, 1989) were carried out on intact seeds of control and SLC1-1-transformed B. napus cv. Hero, and B. carinata, using a Bruker AM wide-bore spectrometer operating at 360 MHz. To reduce anisotropic line broadening, the seeds (35/sample) were rotated at 1 kHz in a zirconium rotor oriented 54.7° to the magnetic field (magic angle sample spinning, MASS).

RESULTS

Acyl-CoA Specificity of Yeast (S. cereviseae; S. pombe) sn-2 Acyltransferase (LPAT)

Yeast cell lysates from both S. cereviseae and S. pombe were assayed for relative sn-2 acyltransferase activity utilizing 18:1 LPA as an acyl acceptor and different radiolabeled acyl-CoAs. The acyl-CoA specificity of the yeast LPATs in vitro was quite broad, and the LPAT was capable of inserting both endogenous (16:0, 18:1) and non-endogenous (18:2, 18:3, 20:1, 22:1 and ricinoleoyl) acyl groups into the sn-2 position of 18:1 LPA, as shown in Table 1 below:

                  TABLE 1                                                          ______________________________________                                         Relative S. cerevisiae and S. pombe acyl-CoA:                                   LPAT activities using 45 μM 18:1-LPA                                        as acyl acceptor                                                                                          LPAT Activity                                                                   .sup.14 C-Acyl-CoA LPAT Activity relative to                                  18:1-                                                supplied nmol/min/mg CoA                                                       (18 μM) protein (%)                                                       ______________________________________                                         S. cerevisiae                                                                    18:1-CoA 3.75 100                                                              18:2-CoA 3.54 94.5                                                             18:1 Δ12- 1.90 50.7                                                      OH--CoA                                                                        20:1-CoA 1.92 51.3                                                             22:1-CoA 0.33 8.9                                                              S. pombe                                                                       18:1-CoA 1.50 100                                                              18:2-CoA 1.27 84.7                                                             18:1 Δ12- 0.85 56.7                                                      OH--CoA                                                                        20:1-CoA 0.38 25.3                                                             22:1-CoA 0.60 40.0                                                           ______________________________________                                    

Because the yeast LPAT (sn-2 acyltransferase) has a relatively broad specificity, transformation of oilseeds rich in very long-chain fatty acids (A. thaliana, B. napus) with the yeast SLC1-1 gene can be predicted to result in enriched VLCFA content, including the sn-2 position. In addition, yeast SLC1 and SLC1-1 transformants can be predicted to be excellent hosts for transformation with hydroxylase genes from castor (R. communis) and Lesquerella spp. to produce seed oils enriched in hydroxy fatty acids. Alternatively, hydroxylase transformants may be sexually crossed with SLC1-1 or SLC1 transformants.

A. thaliana SLC1-1 Transformant Seed Lipid Analyses:

Data from Arabidopsis thaliana transformation indicates that the gene has a dramatic effect on the total seed lipid content and sn-2 composition of TAGs. A large number of SLC1-1 T₂ transgenic lines (21 of 48) showed significantly increased oil yields over untransformed controls, and pBI121 (without SLC1-1 insert) controls, as shown in Table 2 below:

                                      TABLE 2                                      __________________________________________________________________________     Seed fatty acid contents of untransformed wild-type (u-WT) A. thaliana,        pB1121(-SLC1-1)                                                                  A. thaliana transformants (Controls) and selected T.sub.2 transgenic         lines of                                                                         A. thaliana transformed with the yeast SLC1-1 gene.                            (Values are fatty acid content (μg)/50 seeds).                                      10:1                                                                              18:1                    24:0 +                                      Line 16:0 18:0 c9 c11 18:2 18:3 20:0 20:1 20:2 22:0 22:1 24:1 Total          __________________________________________________________________________     u-WT                                                                               28.2                                                                              12.2                                                                              50.5                                                                              5.7                                                                               101.1                                                                             71.9                                                                              7.7                                                                               74.8                                                                              8.7                                                                               1.9                                                                               8.3                                                                               1.3 372.5                                   Control                                                                        pBI121 28.4 12.4 50.2 4.1 99.9 66.2 6.7 74.0 7.1 tr* 7.2 tr* 360.2                                                     Control                                 3 28.8 12.3 57.4 5.7 114.1 78.8 7.7 82.5 9.6 5.7 8.6 1.7 412.3                                                         7 37.1 18.4 102.9 5.9 111.6                                                  84.4 7.6 71.8 8.0 2.9 7.7 2.7                                                  461.0                                   16 33.0 12.5 62.0 6.2 131.7 95.0 9.0 96.4 12.6 1.7 11.0 2.0 473.0                                                      20 36.3 16.1 87.7 7.6 153.3                                                   95.9 10.7 118.8 11.6 2.5 12.4                                                  3.3 556.4                               21 32.1 14.6 62.5 6.2 121.3 89.1 9.4 89.3 9.9 2.2 9.7 2.4 448.5                                                        22 31.9 13.0 57.3 5.9 113.9                                                   86.7 8.6 85.8 10.2 1.7 9.6 2.0                                                 426.5                                   23 35.4 15.7 72.5 7.5 139.7 95.6 10.5 106.9 12.5 2.3 11.7 2.6 512.7                                                    26 32.6 14.5 67.2 6.4 124.1                                                   87.6 9.7 94.4 10.3 2.3 9.7 2.3                                                 461.1                                   29 29.3 13.5 57.7 6.4 114.0 81.6 9.4 89.5 10.6 1.9 11.0 2.0 426.7                                                      39 32.2 13.7 72.8 6.3 129.3                                                   82.0 8.9 100.2 9.7 2.3 10.3 2.1                                                469.7                                   42 24.4 11.7 58.6 5.2 123.0 83.0 11.8 103.6 11.8 2.6 17.4 3.3 456.2                                                    52 33.4 15.1 78.3 6.5 116.9                                                   57.8 11.2 110.0 9.0 2.5 12.6 3.0                                               456.2                                   54 33.0 14.0 73.1 6.8 131.3 91.2 10.1 119.5 11.5 3.0 11.6 1.3 506.3          __________________________________________________________________________      tr* = trace; <0.2 wt %                                                   

In certain of these SLC1-1 T₂ lines, the proportion of VLCFA-containing TAGs (e.g. in Tables 3 and 4), and hence, seed content of total VLCFAs, especially eicosenoic acid and erucic acid, were dramatically increased (Table 5). In some cases, the overall proportions of VLCFAs were also increased (Table 6).

Those SLC1-1 transformed T₂ lines showing the most promising results in terms of increased oil content and increased proportions of VLCFA-containing TAGs, were selected and individual seeds planted to give T₃ progeny lines. Lipid analyses of TAGs from several independent SLC1-1 transgenic T₃ lines indicated that there was significantly increased total lipid content (reported as μg fatty acids/100 seeds; Table 7) which correlated with increased TAG content (nmol TAG/100 seeds; Table 8), compared to pBI121 Control T₃ transformants. In particular, the amounts of VLCFAs (μg/100 seeds; Table 7) and levels of VLCFA-containing C₅₈ and C₆₀ TAGs (Table 8), were greatly enhanced in several SLC1-1 transformants, over pBI121 control plants.

Stereospecific analyses of TAGs from selected independent T₃ SLC1-1 transgenics contained increased proportions of VLCFAs (e.g. eicosenoic acid, 20:1) at the sn-2 position. This trend was consistent, regardless of whether the data was expressed as the proportion, among all sn-2 position fatty acids, which is represented by eicosenoic acid, or as the proportion of total eicosenoic acid in TAGs which is found at the sn-2 position (Table 9). Furthermore, in the SLC1-1 transgenics, the increase in proportions of VLCFAs (e.g. eicosenoic acid) at the sn-2 position of TAGs was correlated with a concomitant decrease in the proportions of polyunsaturated fatty acids at this position, in comparison to pBI121 control plants (FIG. 4).

                                      TABLE 3                                      __________________________________________________________________________     TAG Species Accumulating in T.sub.2  Seeds of Untransformed WT Control          A. thaliana, and SLC1-1 Transformant #42 (nmol/50 seeds ± SD)              Line TAG C#→                                                                         C.sub.50                                                                          C.sub.52                                                                          C.sub.54                                                                           C.sub.56                                                                          C.sub.58                                                                          C.sub.60                                                                          Total                                          __________________________________________________________________________     WT Con                                                                              nmol ±                                                                              5.9                                                                               44.3                                                                              115.3                                                                              163.3                                                                             56.9                                                                              5.9                                                                               391.6                                            (n = 5) SD 0.3 3.2 10.3 16.3 7.3 1.4 37.3                                       mol % ± 1.5 11.3 29.5 41.7 14.5 1.5 100.0                                   SD 0.1 0.4 0.7 0.4 0.8 0.3                                                     mol % C.sub.56 -C.sub.60 57.7                                                 42 nmol ± 3.5 32.7 108.1 194.3 95.6 16.6 450.8                              (n = 2) SD 0.1 0.2 0.9 0.4 1.2 0.8 3.5                                          mol % ± 0.8 7.2 24.0 43.1 21.2 3.7 100.0                                    SD 0.01 0.01 0.004 0.3 0.1 0.2                                                 mol % C.sub.56 -C.sub.60 68.0                                               __________________________________________________________________________

                                      TABLE 4                                      __________________________________________________________________________     TAG Species Accumulating in T.sub.2  Seeds of Untransformed WT Control A.      thaliana, and                                                                   SLC1-1 Transformant #16 (nmol/50 seeds ± SD)                               __________________________________________________________________________     WT Con                                                                              nmol    5.9 44.3                                                                               115.3                                                                              163.3                                                                              56.9                                                                               5.9 391.6                                       (n = 5) SD 0.3 3.2 10.3 16.3 7.3 1.4 37.3                                       mol % 1.5 11.3 29.5 41.7 14.5 1.5 100.0                                        SD 0.1 0.4 0.7 0.4 0.8 0.3                                                     mol % C.sub.56 -C.sub.60 57.7                                                 16 nmol 6.5 51.3 144.1 214.9 82.7 10.6 510.1                                   (n = 2) SD 0.1 0.3 1.4 2.9 2.0 0.6 7.1                                          mol % 1.3 10.1 28.3 42.1 16.2 2.1 100.0                                        SD 0.04 0.1 0.1 0.02 0.2 0.1                                                   mol % C.sub.56 -C.sub.60 60.4                                               __________________________________________________________________________

                  TABLE 5                                                          ______________________________________                                         Eicosenoic (20:1), Eurcic (22:1) and Total Very-Long Chain                       Fatty Acid (VLCFA) Content of T.sub.2  Seed In Untransformed                   WT Control A. thaliana, pBI121 Controls and SLC1-1                             Transgenic Lines (μg/50 seeds)                                                 Line      20:1       22:1 Total VLCFAs                                    ______________________________________                                         WT Con     74.8       8.3    102.8                                               SD (n = 5) 6.4 0.7 10.1                                                        pBI121 Con 73.8 7.0 96.7                                                       SD (n = 2) 2.3 0.3 3.4                                                         16 96.4 11.0 132.6                                                             20 118.8 12.4 159.2                                                            23 106.9 11.7 146.4                                                            42 103.6 17.4 150.3                                                            52 110.0 12.6 148.2                                                            54 119.5 11.6 156.8                                                          ______________________________________                                    

                  TABLE 6                                                          ______________________________________                                         Proportions of Eicosenoic Acid (20:1), and Total VLCFAs                          in T.sub.2  Seed of Untransformed WT Controls (u-WT),                          pBI121 Controls, and Selected SLC1-1 Transgenic Lines of                       A. thaliana (wt % in 50-seed samples)                                          Line              20:1   All VLCFAs                                          ______________________________________                                         u-WT Con        20.0   27.6                                                      pBI121 Con 20.5 26.3                                                           42 22.7 33.0                                                                   52 24.1 32.5                                                                   54 23.6 31.0                                                                 ______________________________________                                    

                  TABLE 7                                                          ______________________________________                                         Total Lipid Content (μg total FA/100 seeds) and VLCFA Content                 (μg/100 seeds) in Mature T.sub.3  Seed of pBI121 Controls (pBI121         Con),                                                                            and Selected SLC1-1 Transgenic Lines of A. thaliana (μg/100 seeds)          Line            Total Lipid Content                                                                         VLCFA Content                                   ______________________________________                                         pBI121 Con a  483.5        119.7                                                 pBl121 Con b 568.5 127.2                                                       pBI121 Con c 519.7 125.1                                                       pBI121 Con d 511.3 122.3                                                       pBI121 Con Avg ± 520.7 123.6                                                SE (n = 4) 15.3 1.4                                                            42-1 1137.9 315.5                                                              42-4 851.7 218.6                                                               42-5 984.6 268.0                                                               23-8 1056.1 287.7                                                              52-2 1109.2 307.5                                                              52-5 870.0 253.3                                                               52-6 1039.1 231.6                                                              16-5 1955.3 227.0                                                            ______________________________________                                    

                  TABLE 8                                                          ______________________________________                                         Total TAG Content and C.sub.58  and C.sub.60  TAG Content of Mature            T.sub.3  Seed                                                                    of pBI121 Controls (pBI121 Con), and Selected SLC1-1 Transgenic               Lines of A. thaliana (nmol/100-seed samples)                                    TAG C #→                                                                            C.sub.50                                                                              C.sub.52                                                                            C.sub.54                                                                             C.sub.56                                                                            C.sub.58                                                                            C.sub.60                                                                            Total                           ______________________________________                                         pBI121 Con ±                                                                          8.5    55.3   130.9 145.3                                                                               30.9 nd*  371.0                               SE (n = 6) 0.4 2.6 7.8 9.0 2.7  21.6                                           16-5 12.4 88.2 214.7 251.6 70.5 5.6 642.9                                      23-8 17.7 130.8 333.6 409.0 106.8 8.0 1005.9                                   42-4 11.4 90.7 259.6 366.4 127.7 14.3 870.0                                    52-6 15.2 106.1 252.1 322.7 85.5 6.0 787.7                                   ______________________________________                                          * nd = not detected                                                      

                  TABLE 9                                                          ______________________________________                                         Proportion of 20:1 at the sn-2 Position of TAGs (wt % sn-2 20:1) and            Proportion of Total 20:1 Found at the sn-2 Position of TAGs (wt % of           total 20:1 at sn-2 position) in Mature T.sub.3  Seed of pBI121 Controls        (pBI121 Con), and Selected SLC1-1 Transgenic Lines of A. thaliana              (wt %/100-seed samples)                                                                                  wt % of Total 20:1 at sn-2                                                      Line wt % sn-2 20:1 position *                     ______________________________________                                         pBI121 Con a                                                                               1.7        3.6                                                       pBI121 Con b 0.6 1.1                                                           pBI121 Con c 0.5 0.9                                                           pBI121 Con d 1.6 3.0                                                           16-5 4.2 16.3                                                                  42-1 5.1 8.5                                                                   42-4 7.9 12.8                                                                  42-5 5.3 8.7                                                                   23-8 7.5 12.0                                                                  52-2 6.2 10.0                                                                  52-5 5.8 9.7                                                                   52-6 7.5 12.0                                                                ______________________________________                                          * % of Total 20:1 in sn2 position = (% in [sn2/[3 × % Total 20:1]]       × 100)                                                             

B. napus and B. carinata SLC1-1 Transformant Seed Lipid Analyses:

Several B. napus cv. Hero, cv. Reston, and B. carinata SLC1-1 T₂ transformant seed lines exhibited increased oil content (Table 10) and increased erucic acid content, expressed as μg/mg DW, or as μg/seed (Table 11). In B. napus cvs. Hero and Reston, seeds of several SLC1-1 transgenic lines exhibited increased proportions of erucic acid (Table 12), compared to the corresponding levels in untransformed control plants. Single seed analyses from a selected average untransformed Hero plant (plant 4) and an SLC1-1 transformant line with a promising high oil yield and high erucic acid phenotype (Line 8, plant 6) indicated a distribution of these traits suggestive of a seed population segregating in a typical Mendelian fashion for a single insert (Table 13). Some seeds of Hero Line 8 plant 6, exhibited probable homozygous WT (e.g. seed 8-6I) or homozygous SLC1-1 (e.g. seeds 8-6K and 8-6H) phenotypes for all three traits (high oil yield, increased erucic acid content, increased proportions of erucic acid), while others displayed probable heterozygous WT/SLC1-1 profiles with intermediate values for these three traits (e.g. seed 8-6B).

                  TABLE 10                                                         ______________________________________                                         Oil Yield (% Dry Weight) in T.sub.2  Seeds of Untransformed Control             (Con) and Selected SLC1-1 Transgenic Lines of B. napus cvs. HERO               and RESTON, and in B. carinala breeding line C90-1163 (± SE                 where applicable).                                                                 Line              Oil Yield (% DW)                                        ______________________________________                                         B. napus cv HERO                                                                 Con 40.1 ± 1.7                                                              5-1 46.7                                                                       5-4 48.7                                                                       7-3 45.3                                                                       7-6 46.4                                                                       7-9 44.9                                                                       8-4 45.9                                                                       8-6 50.9                                                                       8-7 44.9                                                                       8-10 45.1                                                                      B. napus cv RESTON                                                             Con 33.4 ± 2.2                                                              1-7 41.9                                                                       1-8 40.5                                                                       2-8 42.1                                                                       2-9 42.2                                                                       Brassica carinata line C90-1163                                                Con 35.9 ± 1.1                                                              B. car 10-1-7 42.8                                                             B. car 2-3-6 39.9                                                            ______________________________________                                    

                  TABLE 11                                                         ______________________________________                                         Erucic Acid Content (expressed as μg/mg DW or μg/seed) in Mature         T.sub.2                                                                          Seeds of Untransformed Control (Con) and Selected SLC1-1                       Transgenic Lines of B. napus cv. HERO, and in B. carinata                      breeding line C90-1163 (± SE for Controls).                                   Line           22:1 (μg/mg DW)                                                                         22:1 (μg/seed)                               ______________________________________                                         Brassica carinata line                                                           C90-1163                                                                       Con 156.4 ± 5.6                                                             10-1-7 180.4                                                                   B. napus cv HERO                                                               Con 195.5 ± 11.7 596.7 ± 40.8                                            5-1 247.9 900.6                                                                5-4 247.4 818.8                                                                7-3 236.1                                                                      7-6 244.8 912                                                                  7-9 229.2 857.6                                                                8-4 235.7 923.2                                                                8-6 270.9 1020.3                                                               8-7 238.5 888.3                                                                8-10 232.7 900.4                                                               3-1                                                                          ______________________________________                                          -- not determined                                                        

                  TABLE 12                                                         ______________________________________                                         Proportions of Erucic Acid (expressed as wt %) in Mature T.sub.2                 Seeds of Untransformed Control (Con) and Selected SLC1-1                       Transgenic Lines of B. napus cvs. HERO and                                     RESTON (± SE for Controls).                                                      Line          wt % 22:1                                                 ______________________________________                                         B. napus cv HERO                                                                 Con 48.6 ± 0.6                                                              5-1 53.1                                                                       5-4                                                                            7-3 52.1                                                                       7-6 52.8                                                                       7-9                                                                            8-4 51.4                                                                       8-5 53.3                                                                       8-7 51.8                                                                       8-10 53.6                                                                      3-1 58.3                                                                       B. napus cv RESTON                                                             Con 34.7 ± 0.2                                                              1-10 36.4                                                                      1-7 35.8                                                                       1-8 37.4                                                                       2-3 36.6                                                                       2-7 41.1                                                                     ______________________________________                                          -- not determined                                                        

                  TABLE 13                                                         ______________________________________                                         Variation in Lipid Content (expressed as μg total fatty acids/seed)          and Erucic Acid Content (expressed as μg 22:1/seed or as wt % 22:1)         in Mature T.sub.2  Single Seeds of Untransformed Control plant 4               and SLC1-1 Transgenic Line-8 plant 6 of B. napus cv. HERO                      (± SE for Averages, AVG).                                                      Line/Seed μg FAs/seed                                                                              μg 22:1/seed                                                                        Wt % 22:1                                   ______________________________________                                         AVG Con 4 1076.7 ± 61.5                                                                            507.1 ± 33.7                                                                          46.9 ± 0.8                                   AVG-8 6 1441.7 ± 67.3 735.4 ± 36.5 51.0 ± 0.6                         8 6G 1324.8 710.8 54.1                                                         8 6H 1704.3 877.1 52.5                                                         8 6I 1175.4 557.3 47.4                                                         8 6J 1206.8 629.4 52.2                                                         8 6K 1694.7 911.1 53.8                                                         8 6A 1351.6 658.6 48.7                                                         8 6B 1304.5 670.6 51.4                                                         8 6C 1221.1 639.1 52.3                                                         8 6D 1449.0 714.3 49.3                                                         8 6E 1678.2 844.6 50.3                                                         8 6F 1748.0 876.8 50.2                                                       ______________________________________                                    

There were measurable increases in the proportions of erucic acid and total VLCFAs at the sn-2 position in several transformant lines of Hero (Table 14). The effect of the yeast transgene on increasing the sn-2 erucic acid content in B. napus was somewhat less dramatic than its ability to change the sn-2 eicosenoic acid content in A. thaliana (c.f. Table 9). However, this is perhaps, not unexpected, based on the relative specificity of the S. cerevisiae sn-2 acyltransferase for eicosenoyl- vs erucoyl-CoA (c.f. Table 1).

                  TABLE 14                                                         ______________________________________                                         sn-2 Erucic Acid and VLCFA Content in Mature T.sub.2  Seeds of                   Untransformed Control and Selected SLC1-1 Transgenic Lines of                  B. napus cv. HERO.                                                             Line/Seed          sn-2 22:1                                                                               sn-2 VLCFAs                                      ______________________________________                                         Hero Control     1.5      3                                                      Hero 8-6 2.8 4.6                                                               Hero 8-6 G (single seed) 3.6 4.44                                              Hero 3-1 4.12 4.12*                                                            Hero 8-10 2.22 3.7                                                           ______________________________________                                          *Erucic acid (22:1) is the only sn2 VLCFA detected.                      

Analyses of TAG species composition by GC, indicated that several SLC1-1 transformant lines of Hero had increased proportions of C₆₂ TAGs, and to a lesser extent, C₆₄ and C₆₆ TAGs (Table 15). The proportions of C₆₂ -C₆₆ TAGs containing 2 or more C₂₂ fatty acids, was dramatically increased in Hero SLC1-1 transgenics (Table 15), primarily at the expense of TAGs containing two (C₅₆) or three (C₅₄) C₁₀ fatty acids (data not shown). A similar increase in the proportion of C₆₂ TAGs was observed in some B. napus cv. Reston SLC1-1 transgenic lines (Table 15).

                  TABLE 15                                                         ______________________________________                                         Proportions of C.sub.62, C.sub.64  and C.sub.66  TAGs (mol %) in Mature         T.sub.2  Seed of Untransformed Control (Con) and Selected SLC1-1               Transgenic Lines of B. napus cvs. HERO and RESTON                              (± SE for Controls).                                                         Line      C.sub.62  C.sub.64                                                                               C.sub.66                                                                               Total C.sub.62 -C.sub.66                 ______________________________________                                         Control 36.72 ± 1.42                                                                          1.32 ± 0.02                                                                           0.10 ± 0.01                                                                         38.14 ± 1.45                              Hero 5-2 51.44 1.61 0.12 53.37                                                 Hero 5-4 48.92 1.95 0.25 51.12                                                 Hero 5-10 56.48 1.45 0.08 58.02                                                Hero 7-1 57.25 2.19 0.14 59.56                                                 Hero 7-5 55.61 1.98 0.09 57.68                                                 Hero 8-4 44.76 2.14 0.25 47.16                                                 Hero 8-8 53.35 2.22 0.22 55.79                                                 Reston                                                                         Control 18.32 0.94 0.06 19.32                                                  1-5 23.88 1.06 0.07 25.01                                                      2-7 31.57 1.42 0.11 33.20                                                    ______________________________________                                    

Analyses of typical control and SLC1-1 B. napus cv. Hero transgenics with respect to the seed-to-seed variation in proportions of C₆₂ TAGs, indicated that the SLC1-1 T₂ seed population was segregating, but that many of the single seeds had considerably higher proportions of C₆₂ TAGs than any of the untransformed controls (Table 16).

                  TABLE 16                                                         ______________________________________                                         Single Seed Analyses for Proportions of C.sub.62  TAGs (mol %) in Mature        T.sub.2  Seeds of Untransformed Control (Con) and SLC1-1                       Transgenic Lines of B. napus cv. HERO (± SE                                 for averages, AVG).                                                                   Line/Seed  C.sub.62  TAGs                                              ______________________________________                                         Hero Con                                                                         4d 38.54                                                                       4e 40.29                                                                       4b 36.88                                                                       4f 38.81                                                                       4g 30.05                                                                       4j 35.95                                                                       4h 42.84                                                                       4l 40.81                                                                       4k 43.28                                                                       Hero Con AVG 38.6 ± 1.35                                                    Hero 8-6                                                                       8-6d 36.36                                                                     8-6a 47.63                                                                     8-6b 54.06                                                                     8-6c 54.81                                                                     8-6f 44.4                                                                      8-6g 56.27                                                                     8-6h 53.11                                                                     8-6l 42.19                                                                     8-6j 51.44                                                                     8-6k 58.4                                                                      Hero 8-6 AVG 51.35 ± 1.82                                                 ______________________________________                                    

Estimates of oil yield increases in SLC1-1 transgenic lines relative to controls, were directly correlated whether expressed on a "per mg dry weight" basis or on a "per seed" basis (FIG. 5), as were estimates of relative oil content by a non-destructive ¹ H-NMR method (FIG. 6). Indeed, the NMR results for increased oil yield were also positively correlated with increased seed weights in the SLC1-1 transgenics (FIG. 7), and indicated that contributions to increased seed dry weight were directly attributable to increased oil, with negligible contribution from seed water (absence of broad water resonance between the CH₂ OCO-- and CHOCO-- chemical shifts). Typical ¹ H-NMR responses from 35-seed samples of control and "high oil" SLC1-1 transgenic lines of B. napus cv. Hero and B. carinata, are depicted in Table 17.

                  TABLE 17                                                         ______________________________________                                         .sup.1 H-NMR Integral Response for Resonances Assigned to                        Liquidlike Oil (as described by Rutar; 1989) in Mature T.sub.2                 Seeds of Untransformed Controls and Selected SLC1-1 Transgenic                 Lines of B. napus cv. HERO and B. carinata                                     breeding line C90-1163. (35-seed samples; Responses relative                   to Control integration, set at 1,000)                                             Line           NMR Integral Response                                      ______________________________________                                         B. napus cv HERO                                                                 Control 1.0000                                                                 Hero 5-1 1.5175                                                                Hero 7-3 1.2721                                                                Hero 7-6 1.3875                                                                Hero 7-9 1.3245                                                                Hero 8-4 1.5667                                                                Hero 8-6 1.5297                                                                Hero 8-7 1.4825                                                                Hero 8-10 1.6302                                                               B. carinata cv. C90-1163                                                       Control 1.0000                                                                 B. car. 10-1-7 1.5977                                                          B. car. 2-3-6 1.7548                                                         ______________________________________                                    

Some B. napus cv Westar (Canola) SLC1-1 T₂ transformant seed lines showed increases in the relative proportion of oleic acid, and concomitant decreases in the relative proportions of polyunsaturated fatty acids (18:2 and 18:3) (Table 18). This is in contrast to the predicted effect as cited in the University of Kentucky patent application. Thus, the proportions of mono-unsaturated fatty acids can be increased in edible oils, by expression of SLC1-1. Furthermore, the proportions of saturated very long chain fatty acids in these Canola lines were significantly increased (Table 18).

                                      TABLE 18                                     __________________________________________________________________________     Oleic, Linoleic, Linolenic and Saturated VLCFA Compositions of Untransform     ed                                                                              Control and Selected SLC1-1 Transgenic Lines of B. napus cv. WESTAR            (n = 2 or 3)                                                                        Oleic                                                                              Linoleic                                                                            Linolenic                                                                             Eicosanoic                                                                          Behenic                                                                            Lignoceric                                        Line 18:1c9 18:2 c9,12 18:3 c9,12,15 20:0 22:0 24:0                          __________________________________________________________________________     B. napus cv                                                                      WESTAR                                                                         Control 61.03 17.55 11.07  0.55 0.31 0.27                                      WS-13 70.03 14.80 3.41 0.76 0.49 0.56                                          WS-15 71.92 12.33 3.71 0.78 0.53 0.48                                          WS-16 71.06 12.29 3.87 0.97 0.59 0.56                                          WS-15a 72.71  9.69 3.09 0.94 0.65 0.68                                       __________________________________________________________________________

LPAT Analyses of Transformant Lines:

Samples of B. napus cv. Westar and B. napus cv. Argentine SLC1-1 T₁ transformant lines exhibited increased leaf 18:1-CoA:LPAT activities in rapidly-expanding leaf homogenate preparations compared to those from untransformed control plants (Table 19).

Developing seed LPAT analyses in untransformed control and SLC1-1 transgenics of B. napus cv. Hero and B. carinata indicated that both 18:1-CoA:LPAT and 22:1-CoA:LPAT (Table 19) specific activities were dramatically increased in the SLC1-1 transgenics.

Developing seed LPAT analyses of untransformed control and SLC1-1 transgenics of A. thaliana indicated that 20:1-CoA:LPAT activity was increased in several SLC1-1 transgenics (Table 19).

Thus, in this deposition we provide, for the first time, direct evidence that the yeast SLC1-1 gene product encodes an enzyme which possesses sn-2 acyltransferase activity, and which can exhibit LPAT (EC 2.3.1.51) activity in vitro.

                  TABLE 19                                                         ______________________________________                                         Relative LPAT Activities in Homogenates Prepared from T.sub.1  Leaf and         T.sub.2  or T.sub.3  Developing Seed of Untransformed Controls and             Selected SLC1-1 Transgenic Lines of B. napus cvs. WESTAR,                      ARGENTINE and HERO, B. carinata cv. C90-1163, and A. thaliana                  cv. COLUMBIA. All assays conducted as described in                             experimental section.                                                                                           DPM .sup.14 C acyl-CoA                                                            LPAT Activity incorporated into                                              Line Tissue Assayed Assayed PA/μg        ______________________________________                                                                           pr                                           B. napus Westar                                                                          T.sub.1  Leaves                                                                           18:1-CoA                                                    Control   307                                                                  WS 2-5   1008                                                                  WS 3-8   617                                                                   WS 6-7   1428                                                                  B. napus Arg. T.sub.1  Leaves 18:1-CoA                                         Control   350                                                                  Arg 2-8   996                                                                  Arg 3-3   1557                                                                 B. napus Hero T.sub.2  Dev. Seeds 18:1-CoA                                     Control   580                                                                  Hero 3-1   3470                                                                Hero 7-6   2035                                                                Hero 8-6   1370                                                                B. car. C90-1163 T.sub.2  Dev. Seed 18:1-CoA                                   Control   720                                                                  B. car 10-1-7   1125                                                           B. napus Hero T.sub.2  Dev. Seeds 22:1-CoA                                     Control   6.4                                                                  Hero 3-1   68.3                                                                Hero 7-6   53.4                                                                Hero 8-6   20.2                                                                A. thaliana T.sub.3  Dev. Seeds 20:1-CoA                                       WT u-Control   238                                                             42-1   270                                                                     42-4   380                                                                     42-5   503                                                                   ______________________________________                                    

Genetic Analyses of SLC1-1 Transformants:

PCR and Southern analyses data for the transgenic plant lines cited in this deposition are summarized in Table 20.

                  TABLE 20                                                         ______________________________________                                         Summary of PCR and Southern data                                                 for SLC1-1 T.sub.2  transgenic plant lines (nd = not determined)                           Transformant                                                                                             #   Insert (Copy)                        Oilseed (T.sub.2  line) PCR Southern #                                       ______________________________________                                         A. thaliana                                                                              16          +      +      single                                       cv. COLUMBIA 20 + + single                                                      23 + + multiple                                                                42 + + multiple                                                                52 + + multiple                                                                54 + + multiple                                                               B. napus 2 + + multiple                                                        cv. WESTAR 3 + + multiple                                                       6 + + multiple                                                                 13 nd + single                                                                 15 nd + multiple                                                               16 nd + multiple                                                              B. napus 2 + + multiple                                                        cv. ARGENTINE 3 + + multiple                                                   B. napus 5 + + single                                                          cv. HERO 7 + + single                                                           8 + + single                                                                   3 + + single                                                                  B. carinata 10 + + single                                                      cv. C90-1163 2 + + multiple                                                  ______________________________________                                    

To follow the segregation pattern in the T₂ generation of A. thaliana SLC1-1 transformants, seeds from transgenic lines (e.g. lines 16, 20) which showed increases in oil content and amounts of long (C₁₈) and very long chain fatty acids (C₂₀ and C₂₂) were sterilized and germinated on selective medium(50 mg/L kanamycin). Both lines showed the same 3:1 (kanamycin resistant:kanamycin sensitive) segregation pattern which indicates that the marker segregates as one Mendelian locus. Southern hybridization analyses (Southern, 1975) confirmed the presence of a single T-DNA insert per genome. In lines 23, 42, 52 and 54, Southern hybridization analyses suggest that all of the lines have more than one T-DNA insert per genome.

Northern hybridization analyses of seeds at mid-development isolated from siliques of A. thaliana lines 16, 20, 23, 42, 52 and 54 confirmed the expression of SLC1-1 gene in all lines tested, with the highest level of expression in line 42.

Southern analysis of genomic DNA which was isolated from B. napus cv. Westar transgenic lines (2, 3, 6, 13, 15, 16) revealed that only line 13 had a single insert. Both B. napus cv. Argentine SLC1-1 transgenic lines (2, 3) had multiple inserts. B. napus cv. Hero transgenic lines (3, 5, 7, 8) and B. carinata transgenic line 10, each had a single insert, while B. carinata line 2 had multiple T-DNA inserts per genome.

References of Interest to the Present Invention

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5. Brown, A. P., Brough, C. L., Kroon, J. T. M. and Slabas, A. R. (1995) Identification of a cDNA that encodes a 1-acyl-sn-glycerol-3-phosphate acyltransferase from Limnanthes douglasii. Plant Mol. Biol. 29: 267-278.

6. Coleman, J. (1990) Characterization of Escherichia coli cells deficient in 1-acyl-sn-glycerol-3-phosphate acyltransferase activity. J. Biol. Chem. 265: 17215-17221.

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9. Datla, R. S. S., Bekkaoui, F., Hammerlindl, J., Pilate, G., Dunstan, D. I. and Crosby, W. L. (1993) Improved high-level constitutive foreign gene expression in plants using an AMV RNA4 untranslated leader sequence. Plant Science, 94:139-149.

10. De Lange, P., Van Blokland, R., Kooter, J. M., and Mol, J N. M. (1995) Suppression of flavenoid flower pigmentation genes in Petunia hybrida by the introduction of antisense and sense genes. In: Meyer, P. (ed) Gene silencing in higher plants and related phenomena in other eukaryotes. Springer-Verlag, Berlin pp. 57-75.

11. DeBlock, M., DeBrouwer, D., and Tenning, P. (1989) Transformation of Brassica napus and Brassica oleracea using Agrobacterium tumefaciens and the expression of the bar and neo genes in the transgenic plants, Plant Physiol. 91: 694-701.

12. Hitz, W. D., Mauvis, C. J., Ripp, K. G., Reiter, R. J., DeBonte, L. and Chen, Z. (1995) The use of cloned rapeseed genes for cytoplastic fatty acid desaturases and the plastid acyl-ACP thioesterases to alter relative levels of polyunsaturated and saturated fatty acids in rapeseed oil. Proc. 9th Internat'nal Cambridge Rapeseed Congress UK, pp. 470-472.

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16. Knutzon, D. S., Thompson, G. A., Radke, S. E., Johnson, W. B., Knauf, V. C., and Kridl, J. C. (1992) Modification of Brassica seed oil by anti-sense expression of a stearoyl-acyl carrier protein desaturase gene. Proc. Nat'l Acad. Sci. USA, 89: 2624-2628.

17. Knutzon, D. S., Lardizabal, K. D., Nelson J. S., Bleibaum, J. L., Davies, H. M. and Metz, J. (1995a) Cloning of a coconut endosperm cDNA encoding a 1-acyl-sn-glycerol-3-phosphate acyltransferase that accepts medium chain length substrates. Plant Physiol. 109: 999-1006.

18. Knutzon, D. S., Lardizabal, K. D., Nelson J. S., Bleibaum, J. L., and Metz, J. (1995b) Molecular cloning of a medium chain-preferring lyso-phosphatidic acid acyltransferase from immature coconut endosperm. 2nd NPLC Symposium on the Biochemistry and Molecular Biology of Plant Fatty Acids and Glycerolipids, Lake Tahoe, Calif.; Abstr. P-211.

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21. Lassner, M. W., Levering, C. K., Davies, H. M., and Knutzon, D. S. (1995) Lysophosphatidic acid acyltransferase from meadowfoam mediates insertion of erucic acid at the sn-2 position of triacylglycerol in transgenic rapeseed oil. Plant Physiol. 109: 1389-1394.

22. Lester, R. L., Wells, G. B., Oxford, G. and Dickson, R. C. (1993) Mutant strains of Saccharomyces cerevisiae lacking sphingolipids synthesize novel inositol glycerolipids that mimic sphingolipid structures. J. Biol. Chem. 268: 845-856.

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25. Nagiec, M. M., Wells, G. B., Lester, R. L., and Dickson, R. C. (1993) A suppressor gene that enables Saccharomyces cerevisiae to grow without making sphingolipids encodes a protein that resembles in Escherichia coli fatty acyltransferase. J. Biol. Chem. 268: 22156-22163.

26. Roscoe, T., Delseny, M., Lessire, R. and Renard, M. (1995) Modification of triacylglycerol composition. 2nd NPLC Symposium on the Biochemistry and Molecular Biology of Plant Fatty Acids and Glycerolipids, Lake Tahoe, Calif.; Abstr. P-227.

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34. Van Blokland, R., De Lange, P., Mol, J. N. M., and Kooter, J. M. (1993) Modulation of gene expression in plants by antisense genes. In: Lebleu, B. (ed) Antisense research and applications. CRC Press, Boca Raton, Fla., pp 125-148.

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Patents of Interest to the Current Invention

1. Calgene, Inc. (Patent Applicant); Inventors: Davies, H. M., Hawkins, D., Nelsen, J., Lassner, M.; PCT patent publication WO 95/27791. "Plant lysophosphatidic acid acyltransferases."

2. Calgene Inc. has been granted a US patent (WPI Accession No. 91-348069-48; Biotech Patent News, 6, 1992) governing the use of anti-sense technology in plant cells.

3. duPont de Nemours and Company (Patent Applicant; Inventors: Lightner, J. E., Okuley, J. J.; PCT patent publication WO 94/11516; Published European patent application EP 0668919. "Genes for microsomal delta-12 fatty acid desaturases and related enzymes from plants."

4. Nickerson Biocem. Ltd. (Patent Assignee); Inventors: Slabas A. R. and Brown, A. P.; PCT patent publication WO 94/13814; European patent publication EP 0673424. "DNA encoding 2-acyltransferases."

5. University of Kentucky Research Foundation (Patent Applicant); Authors: Dickson, R. et al.; unpublished pending U.S. patent application Ser. No. 434,039. "A technique for specifying the fatty acid at the sn-2 position of acylglycerol

    __________________________________________________________________________     #             SEQUENCE LISTING                                                    - -  - - (1) GENERAL INFORMATION:                                              - -    (iii) NUMBER OF SEQUENCES: 6                                            - -  - - (2) INFORMATION FOR SEQ ID NO: 1:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 947 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -     (vi) ORIGINAL SOURCE:                                                           (A) ORGANISM: Saccharomyce - #s cerevisiae                            - -     (ix) FEATURE:                                                                   (A) NAME/KEY: CDS                                                              (B) LOCATION:1..909                                                   - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #1:                            - - ATG AGT GTG ATA GGT AGG TTC TTG TAT TAC TT - #G AGG TCC GTG TTG         GTC       48                                                                     Met Ser Val Ile Gly Arg Phe Leu Tyr Tyr Le - #u Arg Ser Val Leu Val             1               5 - #                 10 - #                 15               - - GTA CTG GCG CTT GCA GGC TGT GGC TTT TAC GG - #T GTA ATC GCC TCT ATC            96                                                                        Val Leu Ala Leu Ala Gly Cys Gly Phe Tyr Gl - #y Val Ile Ala Ser Ile                         20     - #             25     - #             30                   - - CTT TGC ACG TTA ATC GGT AAG CAA CAT TTG GC - #T CTG TGG ATT ACT GCG           144                                                                        Leu Cys Thr Leu Ile Gly Lys Gln His Leu Al - #a Leu Trp Ile Thr Ala                     35         - #         40         - #         45                       - - CGT TGT TTT TAC CAT GTC ATG AAA TTG ATG CT - #T GGC CTT GAC GTC AAG           192                                                                        Arg Cys Phe Tyr His Val Met Lys Leu Met Le - #u Gly Leu Asp Val Lys                 50             - #     55             - #     60                           - - GTC GTT GGC GAG GAG AAT TTG GCC AAG AAG CC - #A TAT ATT ATG ATT GCC           240                                                                        Val Val Gly Glu Glu Asn Leu Ala Lys Lys Pr - #o Tyr Ile Met Ile Ala             65                 - # 70                 - # 75                 - # 80        - - AAT CAC CAA TCC ACC TTG GAT ATC TTC ATG TT - #A GGT AGG ATT TTC CCC           288                                                                        Asn His Gln Ser Thr Leu Asp Ile Phe Met Le - #u Gly Arg Ile Phe Pro                             85 - #                 90 - #                 95               - - CCT GGT TGC ACA GTT ACT GCC AAG AAG TCT TT - #G AAA TAC GTC CCC TTT           336                                                                        Pro Gly Cys Thr Val Thr Ala Lys Lys Ser Le - #u Lys Tyr Val Pro Phe                        100      - #           105      - #           110                   - - CTG GGT TGG TTC ATG GCT TTG AGT GGT ACA TA - #T TTC TTA GAC AGA TCT           384                                                                        Leu Gly Trp Phe Met Ala Leu Ser Gly Thr Ty - #r Phe Leu Asp Arg Ser                    115          - #       120          - #       125                       - - AAA AGG CAA GAA GCC ATT GAC ACC TTG AAT AA - #A GGT TTA GAA AAT GTT           432                                                                        Lys Arg Gln Glu Ala Ile Asp Thr Leu Asn Ly - #s Gly Leu Glu Asn Val                130              - #   135              - #   140                           - - AAG AAA AAC AAG CGT GCT CTA TGG GTT TTT CC - #T GAG GGT ACC AGG TCT           480                                                                        Lys Lys Asn Lys Arg Ala Leu Trp Val Phe Pr - #o Glu Gly Thr Arg Ser            145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - TAC ACG AGT GAG CTG ACA ATG TTG CCT TTC AA - #G AAG GGT GCT TTC         CAT      528                                                                     Tyr Thr Ser Glu Leu Thr Met Leu Pro Phe Ly - #s Lys Gly Ala Phe His                           165  - #               170  - #               175               - - TTG GCA CAA CAG GGT AAG ATC CCC ATT GTT CC - #A GTG GTT GTT TCC AAT           576                                                                        Leu Ala Gln Gln Gly Lys Ile Pro Ile Val Pr - #o Val Val Val Ser Asn                        180      - #           185      - #           190                   - - ACC AGT ACT TTA GTA AGT CCT AAA TAT GGG GT - #C TTC AAC AGA GGC TGT           624                                                                        Thr Ser Thr Leu Val Ser Pro Lys Tyr Gly Va - #l Phe Asn Arg Gly Cys                    195          - #       200          - #       205                       - - ATG ATT GTT AGA ATT TTA AAA CCT ATT TCA AC - #C GAG AAC TTA ACA AAG           672                                                                        Met Ile Val Arg Ile Leu Lys Pro Ile Ser Th - #r Glu Asn Leu Thr Lys                210              - #   215              - #   220                           - - GAC AAA ATT GGT GAA TTT GCT GAA AAA GTT AG - #A GAT CAA ATG GTT GAC           720                                                                        Asp Lys Ile Gly Glu Phe Ala Glu Lys Val Ar - #g Asp Gln Met Val Asp            225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - ACT TTG AAG GAG ATT GGC TAC TCT CCC GCC AT - #C AAC GAT ACA ACC         CTC      768                                                                     Thr Leu Lys Glu Ile Gly Tyr Ser Pro Ala Il - #e Asn Asp Thr Thr Leu                           245  - #               250  - #               255               - - CCA CCA CAA GCT ATT GAG TAT GCC GCT CTT CA - #A CAT GAC AAG AAA GTG           816                                                                        Pro Pro Gln Ala Ile Glu Tyr Ala Ala Leu Gl - #n His Asp Lys Lys Val                        260      - #           265      - #           270                   - - AAC AAG AAA ATC AAG AAT GAG CCT GTG CCT TC - #T GTC AGC ATT AGC AAC           864                                                                        Asn Lys Lys Ile Lys Asn Glu Pro Val Pro Se - #r Val Ser Ile Ser Asn                    275          - #       280          - #       285                       - - GAT GTC AAT ACC CAT AAC GAA GGT TCA TCT GT - #A AAA AAG ATG CAT               90 - #9                                                                    Asp Val Asn Thr His Asn Glu Gly Ser Ser Va - #l Lys Lys Met His                    290              - #   295              - #   300                           - - TAAGCCACCA CCACATTTTT AGAGTAGTAT ATAGACCC      - #                       - #    947                                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 2:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 303 amino - #acids                                                 (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: protein                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #2:                            - - Met Ser Val Ile Gly Arg Phe Leu Tyr Tyr Le - #u Arg Ser Val Leu Val         1               5 - #                 10 - #                 15               - - Val Leu Ala Leu Ala Gly Cys Gly Phe Tyr Gl - #y Val Ile Ala Ser Ile                    20     - #             25     - #             30                   - - Leu Cys Thr Leu Ile Gly Lys Gln His Leu Al - #a Leu Trp Ile Thr Ala                35         - #         40         - #         45                       - - Arg Cys Phe Tyr His Val Met Lys Leu Met Le - #u Gly Leu Asp Val Lys            50             - #     55             - #     60                           - - Val Val Gly Glu Glu Asn Leu Ala Lys Lys Pr - #o Tyr Ile Met Ile Ala        65                 - # 70                 - # 75                 - # 80        - - Asn His Gln Ser Thr Leu Asp Ile Phe Met Le - #u Gly Arg Ile Phe Pro                        85 - #                 90 - #                 95               - - Pro Gly Cys Thr Val Thr Ala Lys Lys Ser Le - #u Lys Tyr Val Pro Phe                   100      - #           105      - #           110                   - - Leu Gly Trp Phe Met Ala Leu Ser Gly Thr Ty - #r Phe Leu Asp Arg Ser               115          - #       120          - #       125                       - - Lys Arg Gln Glu Ala Ile Asp Thr Leu Asn Ly - #s Gly Leu Glu Asn Val           130              - #   135              - #   140                           - - Lys Lys Asn Lys Arg Ala Leu Trp Val Phe Pr - #o Glu Gly Thr Arg Ser       145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - Tyr Thr Ser Glu Leu Thr Met Leu Pro Phe Ly - #s Lys Gly Ala Phe         His                                                                                              165  - #               170  - #               175              - - Leu Ala Gln Gln Gly Lys Ile Pro Ile Val Pr - #o Val Val Val Ser Asn                   180      - #           185      - #           190                   - - Thr Ser Thr Leu Val Ser Pro Lys Tyr Gly Va - #l Phe Asn Arg Gly Cys               195          - #       200          - #       205                       - - Met Ile Val Arg Ile Leu Lys Pro Ile Ser Th - #r Glu Asn Leu Thr Lys           210              - #   215              - #   220                           - - Asp Lys Ile Gly Glu Phe Ala Glu Lys Val Ar - #g Asp Gln Met Val Asp       225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - Thr Leu Lys Glu Ile Gly Tyr Ser Pro Ala Il - #e Asn Asp Thr Thr         Leu                                                                                              245  - #               250  - #               255              - - Pro Pro Gln Ala Ile Glu Tyr Ala Ala Leu Gl - #n His Asp Lys Lys Val                   260      - #           265      - #           270                   - - Asn Lys Lys Ile Lys Asn Glu Pro Val Pro Se - #r Val Ser Ile Ser Asn               275          - #       280          - #       285                       - - Asp Val Asn Thr His Asn Glu Gly Ser Ser Va - #l Lys Lys Met His               290              - #   295              - #   300                           - -  - - (2) INFORMATION FOR SEQ ID NO: 3:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 947 base - #pairs                                                  (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -     (ix) FEATURE:                                                                   (A) NAME/KEY: CDS                                                              (B) LOCATION:1..909                                                   - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #3:                            - - ATG AGT GTG ATA GGT AGG TTC TTG TAT TAC TT - #G AGG TCC GTG TTG GTC            48                                                                        Met Ser Val Ile Gly Arg Phe Leu Tyr Tyr Le - #u Arg Ser Val Leu Val              1               5 - #                 10 - #                 15               - - GTA CTG GCG CTT GCA GGC TGT GGC TTT TAC GG - #T GTA ATC GCC TCT ATC            96                                                                        Val Leu Ala Leu Ala Gly Cys Gly Phe Tyr Gl - #y Val Ile Ala Ser Ile                         20     - #             25     - #             30                   - - CTT TGC ACG TTA ATC GGT AAG CAA CAT TTG GC - #T CAG TGG ATT ACT GCG           144                                                                        Leu Cys Thr Leu Ile Gly Lys Gln His Leu Al - #a Gln Trp Ile Thr Ala                     35         - #         40         - #         45                       - - CGT TGT TTT TAC CAT GTC ATG AAA TTG ATG CT - #T GGC CTT GAC GTC AAG           192                                                                        Arg Cys Phe Tyr His Val Met Lys Leu Met Le - #u Gly Leu Asp Val Lys                 50             - #     55             - #     60                           - - GTC GTT GGC GAG GAG AAT TTG GCC AAG AAG CC - #A TAT ATT ATG ATT GCC           240                                                                        Val Val Gly Glu Glu Asn Leu Ala Lys Lys Pr - #o Tyr Ile Met Ile Ala             65                 - # 70                 - # 75                 - # 80        - - AAT CAC CAA TCC ACC TTG GAT ATC TTC ATG TT - #A GGT AGG ATT TTC CCC           288                                                                        Asn His Gln Ser Thr Leu Asp Ile Phe Met Le - #u Gly Arg Ile Phe Pro                             85 - #                 90 - #                 95               - - CCT GGT TGC ACA GTT ACT GCC AAG AAG TCT TT - #G AAA TAC GTC CCC TTT           336                                                                        Pro Gly Cys Thr Val Thr Ala Lys Lys Ser Le - #u Lys Tyr Val Pro Phe                        100      - #           105      - #           110                   - - CTG GGT TGG TTC ATG GCT TTG AGT GGT ACA TA - #T TTC TTA GAC AGA TCT           384                                                                        Leu Gly Trp Phe Met Ala Leu Ser Gly Thr Ty - #r Phe Leu Asp Arg Ser                    115          - #       120          - #       125                       - - AAA AGG CAA GAA GCC ATT GAC ACC TTG AAT AA - #A GGT TTA GAA AAT GTT           432                                                                        Lys Arg Gln Glu Ala Ile Asp Thr Leu Asn Ly - #s Gly Leu Glu Asn Val                130              - #   135              - #   140                           - - AAG AAA AAC AAG CGT GCT CTA TGG GTT TTT CC - #T GAG GGT ACC AGG TCT           480                                                                        Lys Lys Asn Lys Arg Ala Leu Trp Val Phe Pr - #o Glu Gly Thr Arg Ser            145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - TAC ACG AGT GAG CTG ACA ATG TTG CCT TTC AA - #G AAG GGT GCT TTC         CAT      528                                                                     Tyr Thr Ser Glu Leu Thr Met Leu Pro Phe Ly - #s Lys Gly Ala Phe His                           165  - #               170  - #               175               - - TTG GCA CAA CAG GGT AAG ATC CCC ATT GTT CC - #A GTG GTT GTT TCC AAT           576                                                                        Leu Ala Gln Gln Gly Lys Ile Pro Ile Val Pr - #o Val Val Val Ser Asn                        180      - #           185      - #           190                   - - ACC AGT ACT TTA GTA AGT CCT AAA TAT GGG GT - #C TTC AAC AGA GGC TGT           624                                                                        Thr Ser Thr Leu Val Ser Pro Lys Tyr Gly Va - #l Phe Asn Arg Gly Cys                    195          - #       200          - #       205                       - - ATG ATT GTT AGA ATT TTA AAA CCT ATT TCA AC - #C GAG AAC TTA ACA AAG           672                                                                        Met Ile Val Arg Ile Leu Lys Pro Ile Ser Th - #r Glu Asn Leu Thr Lys                210              - #   215              - #   220                           - - GAC AAA ATT GGT GAA TTT GCT GAA AAA GTT AG - #A GAT CAA ATG GTT GAC           720                                                                        Asp Lys Ile Gly Glu Phe Ala Glu Lys Val Ar - #g Asp Gln Met Val Asp            225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - ACT TTG AAG GAG ATT GGC TAC TCT CCC GCC AT - #C AAC GAT ACA ACC         CTC      768                                                                     Thr Leu Lys Glu Ile Gly Tyr Ser Pro Ala Il - #e Asn Asp Thr Thr Leu                           245  - #               250  - #               255               - - CCA CCA CAA GCT ATT GAG TAT GCC GCT CTT CA - #A CAT GAC AAG AAA GTG           816                                                                        Pro Pro Gln Ala Ile Glu Tyr Ala Ala Leu Gl - #n His Asp Lys Lys Val                        260      - #           265      - #           270                   - - AAC AAG AAA ATC AAG AAT GAG CCT GTG CCT TC - #T GTC AGC ATT AGC AAC           864                                                                        Asn Lys Lys Ile Lys Asn Glu Pro Val Pro Se - #r Val Ser Ile Ser Asn                    275          - #       280          - #       285                       - - GAT GTC AAT ACC CAT AAC GAA GGT TCA TCT GT - #A AAA AAG ATG CAT               90 - #9                                                                    Asp Val Asn Thr His Asn Glu Gly Ser Ser Va - #l Lys Lys Met His                    290              - #   295              - #   300                           - - TAAGCCACCA CCACATTTTT AGAGTAGTAT ATAGACCC      - #                       - #    947                                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 4:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 303 amino - #acids                                                 (B) TYPE: amino acid                                                           (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: protein                                            - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #4:                            - - Met Ser Val Ile Gly Arg Phe Leu Tyr Tyr Le - #u Arg Ser Val Leu Val         1               5 - #                 10 - #                 15               - - Val Leu Ala Leu Ala Gly Cys Gly Phe Tyr Gl - #y Val Ile Ala Ser Ile                    20     - #             25     - #             30                   - - Leu Cys Thr Leu Ile Gly Lys Gln His Leu Al - #a Gln Trp Ile Thr Ala                35         - #         40         - #         45                       - - Arg Cys Phe Tyr His Val Met Lys Leu Met Le - #u Gly Leu Asp Val Lys            50             - #     55             - #     60                           - - Val Val Gly Glu Glu Asn Leu Ala Lys Lys Pr - #o Tyr Ile Met Ile Ala        65                 - # 70                 - # 75                 - # 80        - - Asn His Gln Ser Thr Leu Asp Ile Phe Met Le - #u Gly Arg Ile Phe Pro                        85 - #                 90 - #                 95               - - Pro Gly Cys Thr Val Thr Ala Lys Lys Ser Le - #u Lys Tyr Val Pro Phe                   100      - #           105      - #           110                   - - Leu Gly Trp Phe Met Ala Leu Ser Gly Thr Ty - #r Phe Leu Asp Arg Ser               115          - #       120          - #       125                       - - Lys Arg Gln Glu Ala Ile Asp Thr Leu Asn Ly - #s Gly Leu Glu Asn Val           130              - #   135              - #   140                           - - Lys Lys Asn Lys Arg Ala Leu Trp Val Phe Pr - #o Glu Gly Thr Arg Ser       145                 1 - #50                 1 - #55                 1 -       #60                                                                               - - Tyr Thr Ser Glu Leu Thr Met Leu Pro Phe Ly - #s Lys Gly Ala Phe         His                                                                                              165  - #               170  - #               175              - - Leu Ala Gln Gln Gly Lys Ile Pro Ile Val Pr - #o Val Val Val Ser Asn                   180      - #           185      - #           190                   - - Thr Ser Thr Leu Val Ser Pro Lys Tyr Gly Va - #l Phe Asn Arg Gly Cys               195          - #       200          - #       205                       - - Met Ile Val Arg Ile Leu Lys Pro Ile Ser Th - #r Glu Asn Leu Thr Lys           210              - #   215              - #   220                           - - Asp Lys Ile Gly Glu Phe Ala Glu Lys Val Ar - #g Asp Gln Met Val Asp       225                 2 - #30                 2 - #35                 2 -       #40                                                                               - - Thr Leu Lys Glu Ile Gly Tyr Ser Pro Ala Il - #e Asn Asp Thr Thr         Leu                                                                                              245  - #               250  - #               255              - - Pro Pro Gln Ala Ile Glu Tyr Ala Ala Leu Gl - #n His Asp Lys Lys Val                   260      - #           265      - #           270                   - - Asn Lys Lys Ile Lys Asn Glu Pro Val Pro Se - #r Val Ser Ile Ser Asn               275          - #       280          - #       285                       - - Asp Val Asn Thr His Asn Glu Gly Ser Ser Va - #l Lys Lys Met His               290              - #   295              - #   300                           - -  - - (2) INFORMATION FOR SEQ ID NO: 5:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 32 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #5:                            - - AGAGAGAGGG ATCCATGAGT GTGATAGGTA GG       - #                  - #               32                                                                       - -  - - (2) INFORMATION FOR SEQ ID NO: 6:                                     - -      (i) SEQUENCE CHARACTERISTICS:                                                  (A) LENGTH: 33 base - #pairs                                                   (B) TYPE: nucleic acid                                                         (C) STRANDEDNESS: single                                                       (D) TOPOLOGY: linear                                                  - -     (ii) MOLECULE TYPE: DNA (genomic)                                      - -     (xi) SEQUENCE DESCRIPTION: SEQ ID NO: - #6:                            - - GAGGAAGAAG GATCCGGGTC TATATACTAC TCT       - #                  - #              33                                                                     __________________________________________________________________________ 

We claim:
 1. A transgenic plant characterized in that said plant has a genome incorporating an expressible yeast SLC1-1 gene having the nucleotide sequence of SEQ ID NO:1 or an expressible yeast SLC1 gene having the nucleotide sequence of SEQ ID NO:3.
 2. A plant according to claim 1 characterized in that said plant consistently exhibits improved seed oil yield and/or a different seed oil composition compared with control plants of the same genotype grown under identical environmental conditions and at the same time, that do not contain either SEQ ID NO:1 or SEQ ID NO:3.
 3. A plant according to claim 1 characterized in that said plant produces non-edible oils.
 4. A plant according to claim 1, characterized in that said plant produces edible oil.
 5. A plant according to claim 1, characterized in that said plant is Arabidopsis thaliana modified to include said SLC1-1 gene or said SLC1 gene.
 6. A plant according to claim 1, characterized in that said plant is a member of the Brassicaceae modified to include said SLC1-1 gene or said SLC1 gene.
 7. A plant according to claim 1, characterized in that said plant is Brassica napus modified to include said SLC1-1 gene or said SLC1 gene.
 8. A plant according to claim 1, characterized in that said plant is Brassica carinata modified to include said SLC1-1 gene or said SLC1 gene.
 9. A plant according to claim 1, characterized in that said plant is selected from the group consisting of borage (Borago spp.), canola, castor (Ricinus communis), cocoa bean (Theobroma cacao), corn (Zea Mays), cotton (Gossypium spp), Crambe spp., Cuphea spp., flax (Linum spp.), Lesquerella and Limnanthes spp., linola, nasturtium (Tropaeolum spp.), Oenothera spp., olive (Olea spp.), palm (Elaeis spp.), peanut (Arachis spp.), rapeseed, safflower (Carthamus spp.), soybean (Glycine and Soja spp.), sunflower (Helianthus spp.), tobacco (Nicotiana spp.) and Vernonia spp., modified to include said SLC1-1 gene or said SLC1 gene.
 10. A plant according to claim 1, containing an endogenous gene that encodes lyso-phosphatidic acid acyltransferase, characterized in that expression of said endogenous gene has been suppressed.
 11. A seed of a transgenic plant characterized in that said seed has a genome incorporating an expressible yeast SLC1-1 gene having the nucleotide sequence of SEQ ID NO:1 or an expressible yeast SLC1 gene having the nucleotide sequence of SEQ ID NO:3.
 12. A seed according to claim 11 characterized in that said seed produces non-edible oils.
 13. A seed according to claim 11 characterized in that said seed produces edible oil.
 14. A seed according to claim 11 characterized in that said seed is a seed of Arabidopsis thaliana modified to include said gene SLC1-1 gene or said SLC1.
 15. A seed according to claim 11 characterized in that said seed is a seed of a member of the Brassicaceae modified to include said SLC1-1 gene or said SLC1 gene.
 16. A seed according to claim 11 characterized in that said seed is a seed of Brassica napus modified to include said SLC1-1 gene or said SLC1 gene.
 17. A seed according to claim 11 characterized in that said seed is a seed of Brassica carinata modified to include said SLC1-1 gene or said SLC1 gene.
 18. A plant according to claim 11 characterized in that said seed is a seed of a plant selected from the group consisting of borage (Borago spp.), castor (Ricinus communis), cocoa bean (Theobroma cacao), corn (Zea Mays), cotton (Gossypium spp), Crambe spp., Cuphea spp., flax (Linum spp.), Lesquerella and Limnanthes spp., nasturtium (Tropaeolum spp.), Oenothera spp., olive (Olea spp.), palm (Elaeis spp.), peanut (Arachis spp.), safflower (Carthamus spp.), soybean (Glycine and Soja spp.), sunflower (Helianthus spp.), tobacco (Nicotiana spp.) and Vernonia spp., modified to include said SLC1-1 gene or said SLC1 gene.
 19. A seed according to claim 11 containing an endogenous gene that encodes lyso-phosphatidic acid acyltransferase, characterized in that expression of said endogenous gene has been suppressed.
 20. Plasmid pSLC1-1/pRD400 (ATCC 97545).
 21. Agrobacterium tumefaciens strain GV3101 characterized in that, into said strain has been introduced a yeast SLC1-1 gene having the nucleotide sequence of SEQ ID NO:1.
 22. A method of producing a transgenic plant, characterized in that an expressible yeast SLC1-1 gene having the nucleotide sequence of SEQ ID NO:1 or an expressible yeast SLC1 gene having the nucleotide sequence of SEQ ID NO:3, is introduced into the genome of said plant.
 23. A method according to claim 22 when said plant contains an endogenous gene that encodes lyso-phosphatidic acid acyltransferase, further characterized by suppressing expression of said endogenous gene that encodes lyso-phosphatidic acid acyltransferase already present in the transfenic plant.
 24. A method of producing a transformed plant having improved resistance to biological and environmental stresses, compared with control plants of the same genotype grown under identical environmental conditions and at the same time, characterized by introducing into the genome of said plant an expressible yeast SLC1-1 gene or SLC1. 